The genes used to modify MSCs to locally treat HCC include cytokines such as IFN-β [127, 163], IFN-α2b [164], tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) [165], IL-12 [166–168]; immune effector molecule anti-CD3scfv [169] and suicide gene HSV-TK (herpes simplex virus-thymidine kinase) [170]. The gene discussed is TKT; the disease is hepatocellular carcinoma.